Stimulation of cyclo-oxygenase by lidocaine, a pro-lipoperoxidant

Lidocaine, which was recently demonstrated to be a good pro-lipoperoxidant, was tested on in vitro PGs biosynthesis, and on arachidonate-induced arterial hypotension, in the rabbit. In the in vitro experiments, lidocaine alone was a poor stimulant of cyclo-oxygenase, but it enhanced significantly the cyclo-oxygenase activation of uric acid. In the rabbit, lidocaine lowered the i.v. arachidonate dose necessary to obtain a significant drop of blood pressure.     

Intestinal motility increased by tetrodotoxin,lidocaine, and procaine

Zusammenfassung In Untersuchungen an Katzen in vivo wird eine bedeutende Zunahme der Dünndarm-Motilität nach lokalen intraarteriellen Injektionen von Tetrodotoxin, Lidocain und Procain demonstriert. Es wird diskutiert, dass diese Wirkung auf der Blockade eines lokalen neurogenen oder neurohormonalen Hemmungsmechanismus beruht, der an der normalen Kontrolle der Darmmotilität beteiligt ist.     

Interaction of BW755C,a potent inhibitor of lipoxygenase and cyclo-oxygenase,with mitochondrial cytochrome oxidase

Summary The interaction between BW755C (3-amino-1-[m-(trifluoromethyl)phenyl]-2-pyrazoline), a potent inhibitor of both lipoxygenase and cyclo-oxygenase, and respiratory chain in mitochondria and electron transport particles (ETP) from rat livers was examined. BW755C accelerated the oxygen uptake by mitochondria without the addition of substrate for the respiratory chain. Spectrophotometric study revealed that BW755C was quickly oxidized by cytochrome oxidase in mitochondria to a compound possessing an absorption maximum at 524 nm. p-Phenylenediamine (p-diaminobenzene, PPDA), which, like BW755C, serves as an electron donor to cytoschrome oxidase, was shown to inhibit the generation of active oxygen in macrophages; the inhibition was stronger than that of BW755C. These results strongly suggest that the oxidative conversion of BW755C by mitochondrial cytochrome oxidase is associated with its potentially inhibitory action on the active oxygen-generating system in phagocytes.The authors are indebted to Dr M. Hori, Gifu College of Pharmacy and to Dr Y. Orii, Kyoto University for their kind supplies of BW755C and pure cytochrome oxidase, respectively.     

Interaction of BW755C, a potent inhibitor of lipoxygenase and cyclo-oxygenase, with mitochondrial cytochrome oxidase

The interaction between BW755C (3-amino-1-[m-(trifluoromethyl)phenyl]-2-pyrazoline), a potent inhibitor of both lipoxygenase and cyclo-oxygenase, and respiratory chain in mitochondria and electron transport particles (ETP) from rat livers was examined. BW755C accelerated the oxygen uptake by mitochondria without the addition of substrate for the respiratory chain. Spectrophotometric study revealed that BW755C was quickly oxidized by cytochrome oxidase in mitochondria to a compound possessing an absorption maximum at 524 nm. p-Phenylenediamine (p-diaminobenzene, PPDA), which, like BW755C, serves as an electron donor to cytochrome oxidase, was shown to inhibit the generation of active oxygen in macrophages; the inhibition was stronger than that of BW755C. These results strongly suggest that the oxidative conversion of BW755C by mitochondrial cytochrome oxidase is associated with its potentially inhibitory action on the active oxygen-generating system in phagocytes.     

Release of labile cyclo-oxygenase products of arachidonic acid from kidney by endotoxin

Summary The possible release of prostaglandin (PG)-like substances was studied in isolated perfused kidneys from intact and from intrarenal endotoxin (Lipopolysaccharide-LPS)-injected rabbits, using the venous outflow superflow superfuse assay organ technique. Injection of LPS into the renal artery of an LPS-pretreated kidney caused a release of thromboxane A₂ (TXA₂) and prostacyclin (PGI₂)-like materials into the venous effluent as verified by the responses of the specific assay organs. No detectable release of these substances was found in the venous outflow of LPS-injected intact kidney. The possible role of labile cyclo-oxygenase products of arachidonic acid in the Shwartzman reaction is discussed.The authors are indepted to Upjohn, Klamazoo (USA) for the generous gift of PGI₂ and to Squibb, New Jersey (USA) for SQ 80338.     

Inhibition of DNA synthesis by lidocaine and procaine

Zusammenfassung Nachweis, dass in Ehrlich-Ascites-Zellen die DNS-Synthese durch Lokalanaesthetika stärker gehemmt wird als die RNS- und die Proteinsynthese.     

Stimulation by D-glucose of mitochondrial respiration

Summary D-glucose increases O₂ uptake by cerebellum mitochondria. This effect is abolished by D-glucose-6-phosphate and D-mannoheptulose. It is proposed that the phosphorylation of D-glucose as catalyzed by bound hexokinase directly affects mitochondrial respiration.     

Stimulation by D-glucose of mitochondrial respiration

D-glucose increases O2 uptake by cerebellum mitochondria. This effect is abolished by D-glucose-6-phosphate and D-mannoheptulose. It is proposed that the phosphorylation of D-glucose as catalyzed by bound hexokinase directly affects mitochondrial respiration.     

Stimulation of RNA polymerase activity by histones,polyamino acids,and polypeptide hormones

Zusammenfassung Decalysin, Polyarginin, Polylysin, Polyornithin, Kalbsthymushistone und Polypeptidhormone stimulieren in niedriger Konzentration die DNA-abhängige RNS-Polymerase-Aktivität vonEscherichia coli, während sie in hoher Konzentration die Enzymaktivität hemmen.     

Stimulation of pyruvate carboxylation by gastric secretagogues

Pyruvate carboxylation was stimulated by 2 gastric secretagogues, histamine and dibutyryl cyclic AMP, and by butyrate. Thiocyanate, an inhibitor of acid secretion, produced a slight decrease. Avidin significantly reduced acid secretion and this effect was overcome by biotin and oxalacetate. The results suggest that carboxylation of pyruvate is one of the reactions controlling oxidative metabolism and acid secretion in toad gastric mucosa.     

Stimulation of pyruvate carboxylation by gastric secretagogues

Summary Pyruvate carboxylation was stimulated by 2 gastric secretagogues, histamine and dibutyryl cyclic AMP, and by butyrate. Thiocyanate, an inhibitor of acid secretion, produced a slight decrease. Avidin significantly reduced acid secretion and this effect was overcome by biotin and oxalacetate. The results suggest that carboxylation of pyruvate is one of the reactions controlling oxidative metabolism and acid secretion in toad gastric mucosa.This investigation was supported by Consejo de Desarrollo Científico y Humanístico de la Universidad del Zulia, and by CONICIT Grant S1-0455.     

Stimulation of sporulation ofClostridium perfringens by papaverine

Summary Papaverine induced sporulation inClostridium perfringens, strains FD-1 and PS52; growth was markedly slowed under these conditions. Papaverine induced sporulation in the presence of glucose, a sporulation repressor, although increasing glucose concentrations overcame the papaverine effect. Papaverine induced sporulation of strain FD-1 more effectively than did theophylline.The author wishes to thank Mrs P.A. Thompson for excellent technical assistance.